Re: 'error: invalid signature' when booting Windows 10

[Pascal Hambourg]

Le 09/12/2018 à 22:04, David Collier a écrit :
> I am trying to retire an old HD where grub /boot directory happens to
> reside, so I am trying to move it to the current Linux root partition which
> is on an SSD.

Did you move/reinstall a new GRUB in an EFI partition on the SSD too ?

> this is the script used to provide a Windows boot option in the Grub menu:
>
> vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
> #!/bin/sh
> exec tail -n +3 $0
> menuentry "Windows 10" {
>     insmod fat
>     insmod chain
>     insmod part_gpt
>
>     set root=(hd1,gpt3)
>     chainloader /efi/Microsoft/Boot/bootmgfw.efi
> }
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> the problem is that when trying to pick this option from grub menu when
> booting from the new location, it reports 'error: invalid signature'. The
> same menu worked fine when it was booting from the old disk (I made double
> checked that (hd1,gptr) points at the correct partition).

I assume you checked the (hdN) drive number did not change.

> I searched this list and found this thread:
> http://lists.gnu.org/archive/html/help-grub/2016-05/msg00020.html but am
> not quite sure how to apply this to the Windows case.

This thread is about GRUB BIOS chainloading, while the above menu entry 
is obviously for GRUB EFI.

For now, the only explanation which comes to my mind is that the active 
GRUB is not GRUB EFI but GRUB BIOS, which expects to chainload a boot 
sector with AA55 signature instead of an EFI executable.